Rotary drillino bir



Aug. 3, 1943.

R. R. cRuM ROTARY DRILLING BIT Filed June 20, 1939 2 Sheets-Sheet 1 INVENTOR. Zak/m E. 671022 xlrfl fizz/W ATTORNEY Aug. 3, 1943. R. R. CRUM 2,325,745

ROTARY DRILLING BIT Filed June 20, 1939 2 Sheets-Sheet 2 I v E N TC R. Za/ na Z /1022 Z/VM/ ATTORNEY I responding cutter 43.

g c a 7 2,325,745

a In order todischarge inud fluidadjacent the top either cutters 43 supported on the outside! i j of th armslland 22, slanting apertures 56 and", r, 51 are; provided. These apertures extend not only-through'thebit head I butalso throughthe topoithe armsll and 22 to providea discharge 1 opening '58 (Fig.4) adjacent the top of thecor- Since'the wings are slanting as described in connection with Figr2, the discharge aperture 58 serves to discharge the, mud fluid along the advancing edges of ,the'cutters 43. g

I WhatI claim a 1. In a rotary drill bit, aim body, a air ofop 1 positely disposed arms attached to-the body,

meansextending inwardly from each arm, and

,integraltherewith cooperating to form ajsubstantially continuous, transverse pin extending be- "tween the arms and havingan axis perpendicular to the body axis, a'pin extending outwardly from.

wellasfon the oblique, pins, said last named cutters operating over substantially the-entire'well 7' borewithin said'zone;

5; Inia rotary 'drillingbit, a body, two pairs 7 I ofarms attached to the body, the arms of each pair being oppositely' disposed about the axis of c said body, eachar n of one pair having an inwardly and downwardly extending pin, rollercut each arm and having an axis oblique tothe axis I i otthe transverse pin, and roller cutters mounted 1 respectively on the pins, the cutters onithe' transveraepin providinga cutting surface extending substantially the entirei distance' between the 1 t 2. In a rotary drill bit,la bitbody, a pair ,of oppositely disposed arms'attached to the body, 1

, f means extending inwardly from each arm and integral therewith, cooperatingtdform a substan- V ,tially continuous 1transyers pin' extending between [the arms and having an axis perpendicw 3 ular to the body axis, a pin extending, outwardly from each arm and havinganaxis obliqueto the axis of the transverse. pin,, and roller cutters mounted respectively on the pins,;the cuttersoni l the transversepin providing a cutting surface ex-Q tending substantially the entire distance between the arms, the obliquity being such that theinneri edge of the outer cutter at thebottorn is close to the outer edge of the inner cutter :atthe bottom,

operate over substantially the entire well bore ters, mounted on said pins arranged to operate over the outer zone of the well bore, eacharm of the other pair having an inwardly aswell as out-u" wardly extending pin, the inwardly extending V pins cooperating ,toiorm a continuous pin extending between said arms andtrans versely of :the [outer cutters, the outwardly extending pins being directed downwardly, androller cutters on; said continuous pin as wellas on said outwardly extending pins, said cutters being arranged to within said zone.

6'. In a rotary drill bit, a body,y'two pairsfof arms attached to the body, the arms of each pair being oppositely disposedabouft the axis of said body, each arm of one pair havingan inwardly, n and downwardly extendingpin; a roller cutter on each of said pins, said cutters being arranged to operate over the outer zone of the well bore, each arm of the other pair having a pin extending outwardly and obliquely to the, axis'of saidjbody, a

whereby the cutters operate over a substantially continuous circular area; i a a 3. In a rotary drilling bit, abody, two pairs oi! ar'ms-attachedtothe bodyythe arms of each; pair-beingoppositelydisposedabout the axis of n said body, onepair of arms carrying roller cut-- a tersarranged to operate over the :outer zone of;

f the well bore, and a crossroller cutterassembly extending transversely lot the outer cutters'and arranged tooperate over substantially the entire r a well borewithin saidzone, the other pair, of arms having pins: serving to support the cross roller, cutter assembly, said armsbeing positioned interl [mediate the ends of said cutterassembly. 1

roller cutter on each ofthe last mentioned pins;

'said cutters being-arranged to operate over an in- I I termediate zone, adjoining said outer 1 zone, said last mentioned arms also each having an inward- 1y extending pin,anda,rol1er cutter, on the last mentionedpin arranged to operate from the cen- .ter of the well bore to said intermediatezone, the I l obliquity of said 1 outwardly extending pins being such that the inner edges of the cutters supported thereon are'at the bottom close to the outer edges a of the respective inside cutters at the bottom.

r 4. In a rotaryfldiilling bit, a body, two pairs of arms attachedto the body,- the arms of each gfpair being oppositely disposed about the axis of, 1

said body, onelpair of arms carrying roller cut ters arranged to operate over the outer zone of the fwell bore, meansextending inwardlyfrom each-i j arm ofthe other pair. and cooperating to form a V substantiallycontinuous plnj between said arms, said pin extendingl transversely of the outer cutters, a .pin extending outwardly from each arm and having an axisoblique m he said continuous pin, and roller cuttersgon the continuous pin asi MROLAND gem/1., 

